Reduction and internal fixation for atlantoaxial dislocation with posterior screw-rod fixation system

Abstract

Objective To evaluate the outcome of posterior screw-rod fixation system in reduction and internal fixation of atlantoaxial dislocation. Methods A retrospective study was done on 27 patients with atlantoaxial instability including 18 male and 9 female (at age range of 13-51 years, mean 31 years) from January 2007 to May 2009. There were 11 patients with chronic odontoid fractures, five with isolated bone odontoid, seven with transverse ligament rupture of atlas and four with rheumatoid arthritis. Skeletal reduction was performed in all the patients. The anterior atlantodens interval (ADI)ranged from 8 mm to 15 mm, average 11 mm. All the patients underwent an intraoperative reduction by posterior C1 lateral mass and C2 pedicle screws with rod fixation. According to American Spine Injury Association (ASIA) impairment scale, there were eight patients at grade B, 15 at grade C and four at grade D. Results All patients were followed up for 6-24 months (average 13 months), which showed that the neck symptoms were improved, with bony union. The ADI was reduced to 2-4 mm (average 2.8 mm)postoperatively. Postoperative ASIA scale was grade C in four patients, grade D in 12 and grade E in 11.There were no neurologic or vascular complications occurred, or no failure of the internal fixtors, pseudarthrosis or instability. Conclusion Posterior screw-rod fixation system has advantages of simple procedures, few complications and good results and can be used for intraoperative reduction of atlantoaxial dislocation. Key words: Atlant-axial joint; Joint instability; Spinal fusion